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Mechanical principles of static engineering systems
Published in Alan Darbyshire, Charles Gibson, Mechanical Engineering, 2023
Alan Darbyshire, Charles Gibson
Invar is an alloy steel containing around 36% nickel. The combination results in a material with a very low expansivity. It is used in applications such as instrumentation systems where expansion of the components could result in output errors.
Liquefied Natural Gas
Published in Arthur J. Kidnay, William R. Parrish, Daniel G. McCartney, Fundamentals of Natural Gas Processing, 2019
Arthur J. Kidnay, William R. Parrish, Daniel G. McCartney
The capacity of Moss carriers is limited by the size of the independent tanks. Larger carriers typically use membrane tanks. Membrane tanks are non-self-supporting and consist of a thin metal membrane, stainless steel, or Invar (36% nickel steel), supported by the ship’s hull through the thermal insulation. Invar is widely used because it has a very small coefficient of thermal expansion in the operating ranges of the tanks, which are approximately ambient to −260°F (−160°C). Figure 18.31 shows some details of the often used containment system, the Gaztransport Technigaz containment systems (Harper, 2002). The Invar membrane (Gaztransport) design is equal in popularity with the stainless steel (Technigaz) membrane. Figure 18.32 shows an example of a membrane tank carrier.
Metal Mirrors
Published in Anees Ahmad, Handbook of Optomechanical Engineering, 2018
Invar 36, an iron/36% Ni alloy with small amounts of manganese and silicon, is the most common of the invars. Invars with 39 and 42% nickel are less common, but have CTEs closely matched to that of silicon and silicon carbide. Super invar, an alloy with cobalt substituted for some of the nickel, has the lowest CTE but can have an irreversible phase transition at low temperatures that substantially changes properties if the composition departs much from the nominal.
Potential applications of advanced nano-composite materials for space payload
Published in Australian Journal of Mechanical Engineering, 2022
Dhaval A. Vartak, B. Satyanarayana, B. S. Munjal, K. B. Vyas, Pina Bhatt, A. K. Lal
Invar is a high density material, it is widely used in space applications for thermal stability due to its low coefficient of thermal expansion (CTE) (Indian Remote Sensing Missions & Payloads 2018). Carbon Fibre has low CTE compared to Epoxy. CTE of Epoxy can be reduced by adding the CNT as shown in Figure 13 (Rawal, Brantle, and Karabudak 2013). Thus, CFRPCNT composites can be replaced Invar brackets & housing of optical payloads. The Electro-optical module of remote sensing payloads includes CCD detectors and detector electronics as shown in Figure 14 (Space Applications Centre SAC -ISRO 2016). These detectors are coupled with optical systems through invar housings. To minimise the variations with temperature gradients, assemblies are coupled through invar plates. The super invar is used for mirror mounts that have been designed to withstand storage temperature and mechanical loads generated during the launch resulted in the reduction of the modulator transfer function (MTF) due to temperature variation within operating temperature.
Design and analysis of dual-constituent lattice sandwich panel with in-plane zero thermal expansion and high structural stiffness
Published in Mechanics of Advanced Materials and Structures, 2021
Zihao Yang, Yongcun Zhang, Shutian Liu, Zhangming Wu
One direct method is to manufacture the lattice sandwich panels using natural bulk materials with low or zero CTEs. However, the inherent defects such as narrow control range of ZTE and poor mechanical performance limit their practice applications. For example, Invar is a robust material, but exhibits low thermal expansion attribute only between 0 and 100°C. Zerodur has low thermal expansion coefficient over a larger temperature range, however, it is a type of glass ceramic that is not appropriately used for reliable load carrying structures. Fiber-reinforced [5] or particulate-reinforced [6] composites can achieve near-zero CTEs through embedding fibers or particulates of materials with negatives CTEs [7]. However, very few known materials in forms of practices that possess negative CTE can be used as reinforcements. Furthermore, great difference on CTEs between the fiber (or particulate) and the matrix may cause interface cracking on heating, which inevitably leads to the delamination failure.
Research progress of diamond/aluminum composite interface design
Published in Functional Diamond, 2022
Zengkai Jiao, Huiyuan Kang, Bo Zhou, Aolong Kang, Xi Wang, Haichao Li, Zhiming Yu, Li Ma, Kechao Zhou, Qiuping Wei
The rapid development of information technology has promoted the progress of electronic devices to integration, miniaturization, and lightweight. Back in 1965, Intel co-founder Gordon Moore formulated his famous Moore’s law: The number of transistors on a chip would double every 12 months. However, the high integration of electronic components makes the power density increase continuously, and the calorific value rises sharply. The problem of heat dissipation poses a severe challenge to the development of the electronic information industry. A new international roadmap for semiconductor technology will no longer follow Moore’s Law if the heat dissipation problem has not been solved [1–3]. The heat dissipation problem has increasingly promoted the development of thermal management materials. Common thermal management materials include polymers, ceramics, metals, and metal matrix composites. Among these, metal matrix composite has become one of the research hotspots. It uses metal or alloy as the matrix, utilizes the second phase with high quality to strengthen the body, displaying excellent performance of each component. Table 1 lists the main properties of common metals and metal-based thermal management materials [4]. Among them, metals such as Al and Cu are low-cost, easy to process, and exhibit high thermal conductivity, but their high thermal expansion coefficient limits their application. Invar and Kovar alloys have a low thermal expansion coefficient, but low thermal conductivity and high density. W-Cu, Mo-Cu, SiC/Al, and other materials have thermal expansion coefficients matching with semiconductor materials such as Si and GaAs, but their thermal conductivity is mostly below 200w/(m k), which is difficult to meet the heat dissipation requirements of high-power integrated circuits.